article: One evening , my dad asked me to buy some bread for dinner . It was dark and cold outside . I rode a bike to a shop near my school . When I left the shop ,it got even darker , so I got on my bike right away. Then I found a woman in a white dress riding a motorcycle after me . She followed me for a long time . I rode very fast and started to cry for help, but no one was there . I was too scared and too tired to ride any faster . At last , I gave up . The woman stopped in front of me and said , " Why were you riding so fast , Ken ?It's dangerous !" I looked at the woman . " Oh , It's you, mum !You really scared me . Dad said you wouldn't be back for dinner tonight !"
question: Why did Ken go out that night ?
options: To ride a bike To buy some food To go to cram school To look for his mother